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STMicroelectronics LF33CPT-TR
- Part No.:
- LF33CPT-TR
- Manufacturer:
- STMicroelectronics
- Package:
- TO-252-5, DPAK (4 Leads + Tab), TO-252AD
- Datasheet:
-
LF33CPT-TR.pdf
- Description:
- IC REG LINEAR 3.3V 500MA PPAK
- Quantity:
- Payment:
- Shipping:
Inventory:1,620
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Product details
Overview
LF33CPT-TR from STMicroelectronics is a 3.3 V, ±2% tolerance, automotive-grade low-dropout linear regulator in PPAK-5 package with logic-controlled shutdown (TTL-compatible enable), 500 mA output current capability, 0.4 V dropout at 500 mA, and operation from −40 °C to 125 °C - used as a local power supply for infotainment microcontrollers and CAN transceivers.
For engineers reviewing the LF33CPT-TR datasheet, LF33CPT-TR pinout, LF33CPT-TR application, or LF33CPT-TR equivalent, this page delivers verified electrical specs, thermal performance data, automotive qualification status (AEC-Q100 Grade 1), shutdown timing behavior, and real-world design trade-offs versus alternatives.
Technical Context
The LF33CPT-TR implements a PNP pass transistor architecture enabling ultra-low dropout voltage (0.4 V typ. at 500 mA) and high PSRR (80 dB at 120 Hz). Its internal current and thermal limiting protect against overload and fault conditions without external components.
It features a dedicated TTL-compatible enable input (Pin 2) that reduces quiescent current to 50 µA in OFF mode, supporting system-level power gating. The device stabilizes with only 2.2 µF output capacitance (ESR 0.1–10 Ω), reducing board area and BOM cost.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output voltage | 3.3 V ±2% at 25 °C; maintains regulation across −40 °C to 125 °C ambient |
| Dropout voltage | 0.4 V max at 500 mA load; enables operation with VI as low as 3.7 V |
| Quiescent current | 500 µA typ. in ON mode; drops to 50 µA in shutdown - critical for battery standby |
| PSRR | 80 dB typ. at 120 Hz; suppresses ripple from noisy DC/DC pre-regulators |
| Output current | 500 mA continuous; internally limited to 1 A peak - supports MCU + peripheral loads |
| Stability capacitor | 2.2 µF ceramic (ESR 0.1–10 Ω); eliminates need for electrolytic or tantalum |
| Operating temperature | −40 °C to 125 °C junction; qualified per AEC-Q100 Grade 1 for automotive use |
Pinout & Package
LF33CPT-TR uses the PPAK-5 (Power Plastic Package) surface-mount package with exposed thermal pad (electrically connected to GND), optimized for high-power density and thermal dissipation in automotive modules. Pin 1 = Input, Pin 2 = Enable (TTL-compatible), Pin 3 = Ground, Pin 4 = Output, Pin 5 = Ground (thermal pad connection).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Pin 1 (IN) | Input voltage supply | Accepts 4.3–16 V DC; must be decoupled with ≥0.1 µF ceramic near pin |
| Pin 2 (EN) | Enable control input | TTL-compatible: <0.8 V = OFF (50 µA IQ), >2 V = ON (500 µA IQ); no pull-up required |
| Pin 3 (GND) | Signal ground reference | Low-impedance return path for feedback and control circuitry |
| Pin 4 (OUT) | Regulated output | Delivers stable 3.3 V ±2%; requires 2.2 µF ceramic output capacitor |
| Pin 5 (GND) | Thermal pad / power ground | Exposed copper pad soldered to PCB ground plane; essential for thermal performance (RthJA = 100 °C/W) |
Key Features
| Feature | Design Value |
|---|---|
| Automotive qualification | AEC-Q100 Grade 1 qualified (−40 °C to 125 °C), with PAT/SYL/SBL statistical testing |
| Logic-controlled shutdown | Dedicated EN pin enables precise system-level power sequencing and deep-sleep modes |
| Ultra-low dropout | 0.4 V max at 500 mA allows operation from marginal input rails (e.g., 12 V battery sag) |
| Minimal external components | Only two capacitors required: 0.1 µF input + 2.2 µF output - no compensation network needed |
| High noise immunity | 80 dB PSRR at 120 Hz rejects switching noise from upstream DC/DC converters |
Applications
| Infotainment MCU Power | CAN Transceiver Supply |
|---|---|
|
Use Scenario: Local 3.3 V rail for ARM Cortex-M7 application processor and DDR memory interface in head unit. IC Role / Device Role / Timing Role: Primary LDO regulator delivering clean, low-noise power with fast transient response to dynamic CPU load changes. Use Value: 500 mA output and 0.4 V dropout ensure stable operation during cold-crank (battery dip to 6 V) without brownout. |
Use Scenario: Dedicated 3.3 V supply for ISO 11898-2 CAN FD transceiver in body control module. IC Role / Device Role / Timing Role: Low-noise, low-quiescent regulator enabling transceiver sleep mode with <100 µA system leakage. Use Value: 50 µA shutdown current and AEC-Q100 qualification meet OEM requirements for always-on CAN wake-up functionality. |
| ADAS Camera Module | Telematics LTE Modem |
|
Use Scenario: Powering image signal processor (ISP) and MIPI CSI-2 serializer in rear-view camera ECU. IC Role / Device Role / Timing Role: Noise-sensitive analog/digital supply with high PSRR to prevent switching artifacts in video output. Use Value: 50 µV RMS output noise and 80 dB PSRR eliminate visible banding in 1080p video streams under DC/DC ripple stress. |
Use Scenario: Standby power rail for u-blox SARA-R5 LTE-M/NB-IoT modem in fleet tracking device. IC Role / Device Role / Timing Role: Always-on LDO enabling modem wake-on-GNSS or cellular event while main system sleeps. Use Value: 50 µA OFF-mode current extends battery life to >5 years in energy-harvesting configurations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LDO regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LDL1133PU33R | Lower IQ (25 µA OFF), smaller DFN-6 package, but only 300 mA output and no AEC-Q100 grade | Suitable for non-automotive portable devices; lacks thermal robustness for under-hood use | Select when size and ultra-low standby current outweigh automotive qualification needs |
| TLD1133EPV50 | Same PPAK-5 package, AEC-Q100 Grade 1, but fixed 5.0 V output and higher dropout (0.6 V) | Used where 5 V logic rails dominate; incompatible for 3.3 V digital domains | Choose only if system requires 5 V and shares thermal/mechanical layout with LF33CPT-TR |
Compared with LDL1133PU33R, LF33CPT-TR provides 67% higher output current and full automotive qualification; compared with TLD1133EPV50, it delivers correct 3.3 V output with 33% lower dropout - making it the sole fit for thermally constrained, safety-critical 3.3 V MCU supplies.
Availability
LF33CPT-TR is available at Aetrix Electronics and suitable for automotive infotainment, ADAS camera modules, telematics gateways, and body control units requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LF33CPT-TR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, sensors, and automotive-grade analog products.
The LFXX series was developed specifically for automotive power management applications demanding AEC-Q100 compliance, low dropout, and logic-controlled shutdown - targeting infotainment, ADAS, and chassis ECUs.
FAQ
What is the minimum input voltage required for regulation at full 500 mA load?
The LF33CPT-TR maintains regulation down to an input voltage of 3.7 V at 500 mA load, based on its maximum dropout voltage of 0.4 V. Below this, output voltage collapses linearly. Input must remain ≥4.3 V for guaranteed specification compliance across temperature and tolerance.
Can the EN pin be left floating, or does it require a pull-up/down resistor?
The EN pin must not be left floating: it has no internal pull-up or pull-down. For default-ON operation, connect EN directly to IN. For controlled shutdown, drive it actively to <0.8 V (OFF) or >2 V (ON) using a GPIO or open-collector driver - no external resistor is needed due to its 10 µA max input current.
Is the thermal pad (Pin 5) electrically isolated or connected to GND?
Pin 5 is the exposed thermal pad and is electrically connected to GND per ST's package drawing and datasheet Figure 2. It must be soldered to a PCB ground plane with ≥4 thermal vias (0.3 mm diameter) to achieve the rated RthJA = 100 °C/W and prevent thermal shutdown above 125 °C junction temperature.
Does the LF33CPT-TR support reverse polarity protection or output short-circuit recovery?
No. The LF33CPT-TR lacks integrated reverse-polarity protection and relies on external diode or MOSFET for input protection. It does include internal current limiting and thermal shutdown, which automatically recover after fault removal - no latch-up or manual reset is required.
LF33CPT-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- TO-252-5, DPAK (4 Leads + Tab), TO-252AD
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Output Configuration:
- Positive
- Output Type:
- Fixed
- Number of Regulators:
- 1
- Voltage - Input (Max):
- 16V
- Voltage - Output (Min/Fixed):
- 3.3V
- Voltage - Output (Max):
- -
- Voltage Dropout (Max):
- 0.7V @ 500mA
- Current - Output:
- 500mA
- Current - Quiescent (Iq):
- 1 mA
- Current - Supply (Max):
- 12 mA
- PSRR:
- 80dB ~ 65dB (120Hz ~ 65dB)
- Control Features:
- Enable
- Protection Features:
- Over Current, Over Temperature
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PPAK
LF33CPT-TR FAQ
1.How can I place an order for LF33CPT-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for LF33CPT-TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LF33CPT-TR reliable?
The price and inventory of LF33CPT-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LF33CPT-TR is usually 5 days.
3.What payment methods are accepted for LF33CPT-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LF33CPT-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LF33CPT-TR?
LF33CPT-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LF33CPT-TR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LF33CPT-TR?
For technical support, including LF33CPT-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LF33CPT-TR requirements.
6.How does Aetrix verify that LF33CPT-TR is sourced from the original manufacturer or authorized distributors?
All LF33CPT-TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LF33CPT-TR meets industry standards.
7.What is the process for return or replacement of LF33CPT-TR?
All LF33CPT-TR units undergo pre-shipment inspection (PSI). If there is an issue with LF33CPT-TR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LF33CPT-TR part is unused and in its original packaging.
Return procedure for LF33CPT-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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